A study conducted by spine surgeons at Vancouver General Hospital has found computer-assisted surgery (CAS) with an intraoperative imaging device and 3D navigation system improves outcomes and delivers economic benefits to the healthcare system.

In the first study of its kind, adult spine surgeon Dr. John Street and colleagues at the Vancouver Spine Surgery Institute at Vancouver General Hospital (VGH) recently compared clinical outcomes for two groups of patients. One group received computer-assisted spine surgery (CAS) with Medtronic's O-armTM imaging device and StealthStationTM navigation system, while a control group received surgery with conventional fluoroscopy using the Philips C-arm device.

The study, which observed a total of 5,132 pedicle screws inserted in 502 patients during the study period (2,682 screws in 253 patients in the treatment group and 2,450 screws in 249 patients in the control group), found that the accuracy rate for screw placement was 95.2 per cent for the CAS group, significantly higher than 86.9 per cent for the conventional treatment group.

“CAS technologies provide real-time, 3D images of the bony anatomy of the patient's spine," said Dr. Street. "Adding that extra dimension makes a significant improvement in the accuracy of screw placement."

Only two patients in the CAS group (0.8 per cent) required a re-operation to address symptomatic misplaced screws, compared to 15 patients (6.0 per cent) in the fluoroscopy group. Nine of those patients had a re-operation during their original admission, and six patients were readmitted after discharge to revise malpositioned screws. The difference in revision rate between the CAS group and those in the fluoroscopy group was statistically significant (p=.014).

The O-armTM and StealthStationTMtechnology shows distinct cost benefits, a significant consideration in today's healthcare environment, where new technologies rarely have robust economic data available, and even fewer can claim a strong incremental cost-effectiveness ratio (ICER) with a conservative break-even point.

Based on an estimated cost of re-operation of C$12,618, the study concluded that the O-armTM and StealthStationTM are cost-neutral for sites performing more than 254 pedicle screw implant procedures per year over a period of seven years. As hospitals perform 255 or more procedures, they actually save their health system money.

In this study, the surgeons calculated an ICER of C$15,961 per re-operation avoided for the CAS group, a figure that falls well within the $25,000 or lower threshold amount many health systems use to indicate significant value. Given the ICER, hospitals performing fewer than 255 procedures also benefit from the significant value of the O-arm.

VGH performs between 500 and 600 surgeries per year, according to Dr. Street.

“There is no radiation exposure from the O-Arm as the team is out of the room when the O-arm takes an image of the patient at the beginning of the procedure," said Dr. Street. "That's a vast improvement from cumulative exposure over time even while wearing heavy lead aprons during five- to seven-hour surgeries." Additionally, he pointed out, the amount of radiation patients receive is acceptable and less in total compared to conventional surgery, which requires a CT scan two to three days post-operatively to check on screw placement.

The O-armTM and StealthStationTM technologies also function as educational tools, Dr. Street notes. "This technology not only allows me to show the resident the 3D anatomy lines, but I can watch them as they insert a screw and ensure they have the right direction and angle. You can't measure that in dollars, but that's a huge advance."

Read the study in The Spine Journal. To learn more about the Medtronic O-armTM and StealthStationTM technology, visit Medtronic.ca.

*Disclosure: Medtronic funded the VGH study, published in the January 2016 issue of The Spine Journal (and online October 2015), but did not have input into the data collection, analysis or economic evaluation by the study authors.

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